Tuesday, December 1, 2009

Poor man's HDR for PSP 9

I found this interesting technique for creating a sort of HDR image on DGrin, but it was written for Photoshop. So, I had to find a way to convert it to Paintshop Pro (it should work with any version, but since Corel took the product over, some of the short cut keys have changed). I still like using PSP v9, which was the last version made by JASC.

In order to use this technique, you should have taken your image in your camera's RAW format (or two shots from a tripod with a shot exposed for the highlights and a shot exposed for the darker areas in the image). What I found works best is a shot taken for the darker areas (highlights overexposed), as the RAW recovery produces less digital noise when the image is darkened.

Here is the as-shot image, with areas of the sky, totally overexposed:


Here is the same image underexposed by about 1½ stops in the RAW converter:

Open the images in PSP, and copy the dark image as a new layer on the light image (ctrl-C on the dark image to copy, ctrl-L on the light image to paste as a new layer). You now need to move the dark layer below the light layer, but before you can do that, you have to change the light layer from a background layer to a raster layer. Open the layer palette and right click on the background layer. Select "Promote Background Layer" from the context menu:

(click on image for larger view)

You can now drag the lighter layer above the darker one (or drag the darker one below the lighter one):

Make sure the lighter layer (in this case Raster 2) is selected.

Now add a layer mask to the lighter layer, by right clicking on the layer then selecting "New Mask Layer" then "From Image". In the dialog that pops up, select the file name of the darker image (in this case IMG_6556D.TIF), "Source luminance" and "Invert mask data":


The image already looks appreciably better:


For the next step, we first need to duplicate the dark layer (which is at the bottom of the layer stack). Right click on it and select "Duplicate Layer".


Now drag this new layer to the top of the layer stack:


Add a new mask layer from image as outlined above, but this time do not select "Invert mask data":


After the second mask, some slight changes to the contrast:


Now, for the final editing, you need to make copy of all the blended layers. Select the top layer in the stack and press ctrl-shift-C. This will take a bit of time, especially if your camera has a large sensor. When the processing is finished, press ctrl-L to paste a new layer on the top of the layer stack (you could also merge all layers, but I prefer keeping all the layers in case I want to play around with them in the future).

You can now carry out whatever editing you normally do to a photo (contrast, saturation and sharpening in my case). The final product:

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